Re: [kvm-devel] [PATCH] gfxboot VMX workaround v2

[Guillaume T. <gui...@ex...>]

On Tue, 08 Apr 2008 07:14:13 -0500
Anthony Liguori <an...@co...> wrote:

> Guillaume Thouvenin wrote:
> > On Mon, 07 Apr 2008 11:05:06 -0500
> > Anthony Liguori <an...@co...> wrote:
> >
> >   
> >> Perhaps a viable way to fix this upstream would be to catch the vmentry 
> >> failure, look to see if SS.CPL != CS.CPL, and if so, invoke 
> >> x86_emulate() in a loop until SS.CPL == CS.CPL.
> >>     
> >
> > I tried this solution some time ago but unfortunately x86_emulate()
> > failed. I suspected a problem with guest EIP that could different
> > between the vmentry catch and the emulation. I will rebase my patch and
> > post them on the mailing list.
> >   
> 
> x86 emulate is missing support for jmp far which is used to switch into 
> protected mode.  It just needs to be added.

Ok I see. I understand now why you said in a previous email that KVM
needs to have a proper load_seg() function like the Xen's x86_emulate.
This function is used to load the segment in a far jmp. I will look how
it is done in Xen and I will try to copy the stuff like you did.

Regards,
Guillaume